Various types of skis are conventionally known, for which numerous variants exist. These are constituted by an elongated beam whose front end is curved upward so as to form a tip, the rear end also being curved, but in less pronounced fashion, so as to constitute the heel.
Present-day skis normally have a composite structure in which various materials are combined so that each works optimally, given the distribution of the mechanical stresses during skiing. Accordingly, this structure normally comprises peripheral protective components, internal strengthening elements used to combat flectional and torsional stresses, and a core. The structure also comprises a sliding sole which forms the lower surface of the ski, and lower metal edges forming the lower ridges of the ski. These components are bonded together or injection-assembled, assembly being normally carried out under heat in a mold having the final shape of the ski, a front part sharply raised so as to form a tip, a rear part slightly raised in the shape of the heel, and a central cambered portion.
Present-day alpine skis are fitted with carbon steel edges of the XC50 to XC70 type; i.e., containing from 0.5% to 0.70% carbon. This type of steel makes it possible, after transformation by drawing, rolling, and thermal hardening treatment, to produce, first, the specific profile dimensions of the ski edges and a hardness of 50.+-.2 HRC, or 525.+-.30 Vickers HV10, needed for holding the ground edge; and second, the conventional elastic limit allowing the edge to become elongated by 0.65% without deformation and to withstand the alternating flections of a ski without loss of ski camber, and which makes it possible to withstand accidental shocks against stones, without major damage. A limit of 0.5% can be achieved during skiing when violent, high-speed shocks occur, when the skier falls, etc.
For several years, a main cause of dissatisfaction among users of alpine skis has been the oxidation of the ski edges. Accordingly, a large number of ski manufacturers have tried to remedy this problem by replacing carbon steel grades with grades of the stainless martensitic chrome type, such as those used in cutlery.
To achieve the aforementioned specifications embodied in the ski edge, the grades Z.sub.x and C.sub.y have been selected, "x" being capable of variation between 20 and 40 and "y" being capable of variation between 12 and 14; i.e., steels containing from 0.2 to 0.4% carbon so as to achieve the required hardness after hardening, and containing from 12 to 14% chrome for corrosion resistance.
These attempts have ended in failure, since this type of grade does not make it possible to reach the elastic limit level (0.2% permanent deformation) required for a ski edge (approximately 1350 N/mm.sub.2, corresponding to 0.65% elastic elongation).
Analysis of this limit at 0.01% showed that, for this type of edge, the limit fell to 850 N/mm.sub.2, or 0.4% elongation.